Welsh is part of the demographic coveted by health officials nationwide: the so-called "Young Invincibles." It’s a term long-used by the insurance industry to describe 18- to 34-year-olds who perceive themselves to be invincible and thus consider health insurance unnecessary.

And as the nation prepares to enroll uninsured Americans into health insurance policies under the Affordable Care Act, or "Obamacare" as it’s also known, a lot is riding on these healthy young adults.

The Affordable Care Act requires nearly every American to have health insurance by Jan. 1, 2014, or to pay a fine, which starts out small and grows over time. Covered California's marketplace will open on Tuesday, Oct. 1.

If Young Invincibles buy insurance, they will help balance the cost of caring for older, sicker people. Without them, premiums could skyrocket, endangering one of Obamacare's main goals: affordable insurance.

But while many believe that getting buy-in from young invincibles will pose huge challenges, others are more optimistic.

"Young people do care about health care and people do want affordable health care options," says Tamika Butler, California director of the nationwide advocacy group called, "Young Invincibles."

Butler says the organization began in 2009 to address the "mistaken belief" that young people don’t want health insurance.

"We, just like everyone else, ... get sick. We use the ER more than any other age group outside of seniors," she says of young adults.

Butler points to a recent Young Invincibles poll that found only 5 percent of young adults choose to go without health insurance. Likewise, a national survey by the Kaiser Family Foundation — not affiliated with Kaiser Permanente — found seven in 10 young adults consider health insurance to be "very important." And surveys of 18- to 34-year-olds in California also turned up widespread interest in coverage, says Peter V. Lee, executive director of Covered California, the state-run insurance marketplace formed under the federal health law.

"I like to say they may be young and invincible, but they’re not young and stupid," Lee says. "We’ve actually talked to thousands of them and the number one thing they say is, 'If I could get insurance I could afford, I’d be in. I’d be in the game.' "

Under the ACA, uninsured individuals who make less than four times the federal poverty level –or about $46,000 a year – may qualify for sliding-scale government subsidies. These are tax credits that will cut the cost of monthly insurance premiums.

To qualify for subsidies, Californians must buy their insurance from one of the 12 private companies participating in the Covered California marketplace.

Lee is betting the subsidies will make insurance affordable for young adults who are now priced out of the market.

"What we need to do is to get in front of those folks and show them what it’s going to cost and why having insurance means they aren’t going to lose their truck, they aren’t going to go into debt for the next 30 years," he says.

While Covered California has yet to roll out a campaign that targets this demographic, the Young Invincibles organization has done so. The group has launched a nationwide social media campaign and a mobile app to boost insurance literacy among young Americans, many of whom have no idea what terms such as "co-pay" or "premium" mean, says Butler.

"The biggest challenge is just that information gap, that awareness gap of what’s happening, when it’s happening and why it’s important," she says.

Such efforts to close that information gap among young invincibles is welcome news to Welsh and his friend Colin Waite, a self-employed screen writer from Los Angeles.

Waite turned 26 this year, which now makes him ineligible to receive health insurance under his father’s plan. (The ACA allows young adults to receive coverage under their parents plan until their 26th birthday). Waite says he's is eager to find affordable coverage. Like Welsh, he's hoping the promise of affordable insurance proves true.

"If I could afford the insurance, then obviously I would want to buy it," he says. "There’s a level of peace of mind that comes from having something with the idea that you’ll be able to take care of yourself if something bad were to happen."